From your article:
Sig-1Rs localize at the interface between the endoplasmic reticulum (ER) and mitochondrion, which is known as the mitochondria-associated ER membrane (MAM).
Consequently, they are found in a variety of areas within the central nervous system as well as in other types of cells throughout the body (notably cardiac cells).
An important biological activity of sigma receptor activation is the inhibition of ion channels, which operates through protein-protein interactions without mediation by G proteins and protein kinases. In addition to modulating various types of voltage-activated K+ channels, the sigma-1 receptor associates with the Kv1.4 K+ channel in posterior pituitary nerve terminals, as well as in Xenopus oocytes. Sigma receptor ligands also modulate N-, L-, P/Q-, and R-type Ca2+ channels in rat sympathetic and parasympathetic neurons. Sigmareceptor ligands modulate cardiac voltage-gated Na+ channels (hNav1.5) in human embryonic kidney 293 (HEK293) cells, COS-7 cells, and neonatal mouse cardiac myocytes. To evaluate the capacity of DMT to induce physiological responses by binding to sigma receptors, we examined the action of DMT on voltage-activated Na+ current.
Fontanilla D, Johannessen M, Hajipour AR, Cozzi NV, Jackson MB, Ruoho AE. The hallucinogen N,N-dimethyltryptamine (DMT) is an endogenous sigma-1 receptor regulator. Science. 2009;323:934–937. [DOI]
(reference 24 in the article that you cite)